ALKALOIDS. 395 



Codeine, Codeina, C 18 H 21 NO 3 .H 2 O = 317. A white, crystalline 

 powder, sparingly soluble in cold water, easily soluble in alcohol and 

 chloroform. It is neutral to litmus, and has a faintly bitter taste. 



Analytical reactions: 



1. On adding to 5 c.c. of an aqueous solution of codeine (1 in 100) 

 10 drops of bromine water, shaking so as to redissolve the precipitate 

 formed, and adding after a few minutes some ammonia water, the 

 liquid assumes a claret-red tint. (Plate VII., 3.) 



2. Codeine, dissolved in sulphuric acid containing 1 per cent, of 

 sodium molybdate, forms at first a dirty-green solution, which after 

 a while becomes pure blue, and gradually fades within a few hours 

 to pale yellow. 



3. Codeine, dissolved in sulphuric acid, forms a colorless liquid, 

 which, upon being warmed with a trace of ferric chloride, becomes 

 deep blue. 



4. Crystals of codeine sprinkled upon nitric acid assume a red 

 color, but the acid will acquire only a yellow, not a red color. (Dif- 

 ference from morphine.) 



Narcotine, C, 2 H. 23 N0 7 , and Narceine, C 23 H 29 N0 9 .2H 2 0, are white, crystalline 

 opium alkaloids, which are almost insoluble in water, soluble in alcohol. 

 Concentrated sulphuric acid forms with narcotine a solution which is at first 

 colorless, but turns yellow in a few minutes, and purple on heating. Narceine 

 dissolves in concentrated sulphuric acid with a gray-brown color, which changes 

 to red when heated. 



Meconic acid, C 7 H 4 O 7 .3H 2 O. A tribasic acid, characteristic of 

 opium, in which it exists to the extent of 3 or 4 per cent., most 

 likely combined with the alkaloids. It is a white, crystalline sub- 

 stance, soluble in water and alcohol. 



Meconic acid forms with ferric chloride a blood-red color, which is 

 not affected by dilute acids or by mercuric chloride (different from 

 ferric sulphocyanate), but disappears on the addition of stannous 

 chloride and of the alkali hypochlorites. This test may be used in 

 cases of poisoning to decide whether opium or morphine is present. 



Cinchona alkaloids. The bark of various species of cinchona 

 contains a number of alkaloids, of which the most important are 

 quinine, cinchonine, quinidine, and cinchonidine. These alkaloids 

 exist in the bark in combination with a peculiar acid, termed Jcinic 

 add. The quantity and relative proportion of the alkaloids vary 

 widely in different barks, but the official bark should contain not less 

 than 5 per cent, of total alkaloids, and at least 2.5 per cent, of quinine. 



